As the existing communication technologies which for about a decade have supported railway operations and the huge transition from conventional to modern communication-based signaling approach the extent of their performance capabilities, the railway industry strives to migrate to a proven solution aiming to support the new and diverse broadband services and reduce cost. Long Term Evolution (LTE) radio access technology has been globally accepted because of the unparalleled performance, off-the-shelf convenience, and well-developed standardization. An LTE solution, however, brings both the opportunities and challenges to a Data Communication System (DCS) underlying a Communication-Based Train Control (CBTC) system. The presented research targets one of the main LTE deployment challenges; the spectrum availability. To cope with the increasing scarcity of spectrum resources, LTE/LTE-A has envisaged an extension to the unlicensed band which is already heavily populated with incompatible legacy systems such as the immensely popular Wi-Fi networks. In this paper, a design framework is established to dimension the LTE system according to the CBTC DCS sub-system level requirements. Furthermore, the LTE/Wi-Fi coexistence performance is evaluated and studied in a train control application’s context by using a Markov chain analysis approach.

Current standards such as NFPA 130 [1] require railcar floor assemblies to achieve a fire resistance rating according to ASTM E119 [2] by exposing the assemblies to a prescribed 30 minute time-temperature curve using a furnace. Though the ASTM E119 is a standard test procedure, it does not represent a real fire scenario which can have temporal and spatial varying exposure. This work developed a computational framework to evaluate and compare standard fire exposures such as ASTM E119 to real fire exposures to determine the difference in the temperature rise of a railcar floor assembly. The dimensions of the assembly used in this work consisted of the entire width of the railcar ∼3.0 m (10 ft) and a length of 3.7 m (12 ft) as described in NFPA 130. The real fire exposures simulated in this work have been identified in a review [3] of incidents involving fire exposures to railcars in the US and internationally over the past 50 years. The fire exposures consisted of a continuously fed diesel fuel spill, a localized trash fire, and a gasoline spill simulated from a collision of the railcar with an automobile. These realistic fire exposures were applied to a floor assembly model in Fire Dynamics Simulator (FDS) [4] which also included the undercarriage equipment to better capture the fire dynamics. The thermal exposure at the underside of railcar assembly was extracted using the heat transfer coefficient and the adiabatic surface temperature provided by FDS. These spatial-temporal exposures were coupled with a detailed railcar floor assembly finite element (FE) model in ABAQUS [5] to analyze the thermal behavior of the assembly. The thermal model in ABAQUS provided the evolution of temperature in different components of floor assembly consisting of a structural frame, insulation, and a composite floor. The standard scenarios were simulated for two hours instead of the typical 30 minutes to identify the appropriate exposure duration which can better represent a real fire scenario.

The lateral stability of the continuous welded rail (CWR) depends on a number of parameters which contribute to the progressive loss of the initial alignment of the track and its consequent predisposition to deform sideways, gradually or sharply, with serious risks for the safety both of passengers and operators. Different types of initial lateral defect, in terms of shape and size, are introduced by many authors in their own numerical and analytical model, but essentially all of them can be traced back — except for small “personalizations” — to the model proposed by Andrew Kish, who hypothesized the existence of a misalignment defect having the shape of a sine curve extended for half-wavelength, characterized by amplitude and wavelength values typical of the USA railroads. Moreover, all previous studies focused their attention on the introduction, in a geometrically perfect railway track, of a single defect confined in a zone of finite dimensions and having a rather simple geometry which qualitatively approximates the real defect, with the aim of simplifying the calculation of the buckling temperatures of the track associated with such geometry. In this paper, it was preliminarily analyzed the way the defect introduced in the track affects the critical temperature values. It started with a defect created artificially, applying to a geometrically perfect track and in the absence of thermal loads, a lateral displacement in the central transversal section of the track, and calculating, with the hypothesis of linear elastic behavior, the resulting deformed shape, which was assumed, after zeroing the corresponding stress field, as the input geometry for the subsequent buckling calculation. The deformed shape so obtained, being a Zimmermann deformed shape type, has no geometrical discontinuities near the defect and interprets in a natural way the defected geometry of the track, due to the dependence of its configuration on the flexural stiffness of the entire track in the lateral plane. Afterwards, modeling was carried out taking into account the real behavior of the track after the loss of its rectilinear configuration: the defect was created simulating the response of the track to a momentary lateral load — resulting, e.g., from train passages — which succeeded to cause a permanent displacement resulting from the elastic-plastic response of the track. The deformed shape of the track obtained in this way was used as the input geometry for the calculation of the buckling temperatures, once without resetting the stress field induced in the structure by the loading–unloading hysteresis cycle, and then considering the track free from internal stresses. The results show that both the numerical model that contemplate the defect introduced “plastically”, and that where the track is free from internal stresses, lead to more conservative results against the risk of thermal buckling in railway tracks made with CWR. A better approximation of the realistic representation of a generic defected railway track was pursued considering an indefinite number of defects distributed along the track, where each defect was characterized by different amplitude and wavelength values. The obtained results show that the presence of multiple defects further reduces the safety factor against the thermal track buckling phenomenon. The paper ends with the proposal of an evaluation criterion that takes into account the effects of multiple alignment defects on the critical buckling temperatures in continuous welded rail tracks.

Prevention of bearing failures which may lead to catastrophic derailment is a major safety concern for the railroad industry. Advances in bearing condition monitoring hold the promise of early detection of bearing defects, which will improve system reliability by permitting early replacement of failing components. However, to minimize disruption to operations while providing the maximum level of accident prevention that early detection affords, it will be necessary to understand the defect growth process and try to quantify the growth speed to permit economical, non-disruptive replacement of failing components rather than relying on immediate removal upon detection. The study presented here investigates the correlation between the rate of surface defect (i.e. spall) growth per mile of full-load operation and the size of the defects. The data used for this study was acquired from defective bearings that were run under various load and speed conditions utilizing specialized railroad bearing dynamic test rigs operated by the University Transportation Center for Railway Safety (UTCRS) at the University of Texas Rio Grande Valley (UTRGV). Periodic removal and disassembly of the railroad bearings was carried out for inspection and defect size measurement and documentation. Castings were made of spalls using low-melting, zero shrinkage Bismuth-based alloys so that a permanent record of the full spall geometry could be retained. Spalls were measured using optical techniques coupled with digital image analysis and also with a manual coordinate measuring instrument with the resulting field of points manipulated in MatLab™ and Solidworks™. The spall growth rate in area per mile of full-load operation was determined and, when plotted versus spall area, clear trends emerge. Initial spall size is randomly distributed as it depends on originating defect depth, size, and location on the rolling raceway. The growth of surface spalls is characterized by two growth regimes with an initial slower growth rate which then accelerates when spalls reach a critical size. Scatter is significant but upper and lower bounds for spall growth rates are proposed and the critical dimension for transition to rapid spall growth is estimated. The main result of this study is a preliminary model for spall growth which can be coupled to bearing condition monitoring tools to permit economical scheduling of bearing replacement after the initial detection of spalls.

This paper presents the result of an evaluation program for the condition of the SEPTA Broad Street subway car shells and their capability to perform during an extended period of revenue service. SEPTA currently is evaluating various system upgrades to address equipment obsolescence and reliability, and wanted to verify that the current car shells are expected to be serviceable during this extended period. The evaluation focused on two aspects of the 1982-built car shells. First, what is the current and predicted condition of the shells and, second, how does the performance of the current car shell design compare to present day designs and requirements? Four sets of activities were done as part of this project. One-third of the fleet was randomly chosen for visual inspections. Service-induced cracks were identified at two locations: in ring welds below the doors, and on the side sill between the corner posts and the anti-climbers. The ring weld cracks have been identified on a small number of cars in the past, and SEPTA continues to monitor and reinforce these areas. The cracks between the corner posts and anticlimbers are also being monitored; to date, none of these cracks has progressed to the point that repair is required. In parallel with the visual inspections, the car shell camber and doorway dimensions were measured on approximately 10% of the fleet. All the measured vehicles had positive camber; doorway dimensions were uniform, except for scattered individual measurements that were car-specific. This part of the evaluation concluded that the car shells are not undergoing significant degradation or cracking. One car was instrumented with strain gauges in potential high-stress areas, and then operated at simulated full passenger-load weight over the Broad Street route. Cyclic strains imposed by simulated revenue service were measured and converted to stresses. This testing confirmed high stresses at the joint between the side sill and the body bolster. The lifetime limiting location on the car shells is in the ring welds below the doors, consistent with the results of the visual inspections. Using conservative assumptions of continuous full passenger loading and minimum material properties, the predicted lifetime to the initiation of visible cracks in this area is 7–14 years of service. This independent evaluation is consistent with the actual experience, and provided confidence in the analysis protocol. SEPTA is monitoring this location and repairing cracks as required. Evaluation of the car shell design with regard to performance in a collision revealed that, unlike most other cars of its era, the Broad Street car shell contains provisions to manage energy absorption during a low-speed collision. Records obtained from a car repair shop showed that, when a Broad Street car had a significant non-revenue end collision, these provisions worked as intended to localize the deformation. In similar collisions, the Broad Street car shell will not perform significantly different from cars built to current industry practices. Results from this study indicate that with continued attention to car shell condition, including regular inspections and limited repairs, the Broad Street car shells will continue to be safe and serviceable for an extended period.

The primary purpose of this study is to use a nano-scale optical surface profilometer to assess the feasibility of such instruments in measuring localized friction coefficient on railways, beyond what can be commonly measured by tribometers used by the railroad industry. One of the important aspects of moving freight and passengers on railways is the ability to manage and control the friction between the rails and wheels. Creating a general friction model is a challenging task because friction is influenced by various factors such as surface metrology, properties of materials in contact, surface contamination, flash temperature, normal load, sliding velocity, surface deformation, inter-surface adhesion, etc. With an increase in the number of influencing factors, the complexity of the friction model also increases. Therefore, reliable prediction of the friction, both theoretically and empirically, is sensitive to how the model parameters are measured. In this study, the surface characteristics of four rail sections are measured at 20 microns over a rectangular area using a portable Nanovea JR25 optical surface profilometer and the results were studied using various statistical procedures and Fractal theory. Furthermore, a 2D rectangular area was measured in this study because 1D height profile doesn’t capture all the necessary statistical properties of the surface. For surface roughness characterization, the 3D parameters such as root-mean-square (RMS) height, skewness, kurtosis and other important parameters are obtained according to ISO 25178 standard. To verify the statistical results and fractal analysis, a British Pendulum Skid Resistance Tester is used to measure the average sliding coefficients of friction based on several experiments over a 5 cm contact length for the four rail sections selected for the tests. The results indicate that rail surfaces with lower fractal dimension number have a lower friction. The larger fractal dimension number appears to be directly proportional to larger microtexture features, which potentially increase friction.

The connection between bearing raceway condition and fatigue in tapered roller bearings utilized in the railroad environment is of interest. Roller bearings for railroad applications are typically precision ground to exact dimensions with crowned contact geometries for optimal loading of components. This normally results in completely elastic Hertzian contact stresses under standard railcar loads with original equipment manufacturer raceway contact geometries. However, with extremely uneven bogie load distributions, impact damage, corrosion and spall repair, imperfect stress distributions can occur on bearing raceways utilized in the railroad environment. Railroad bearing applications in North America have the added complexity that the life of the product is not defined in the same way as in other industries. For example, the definition of spalling remains consistent across all industries and is outlined in the Association of American Railroads (AAR) Manual of Standards and Recommended Practices. However, an inconsistency compared to other industries is that the fatigue life of the product in the rail industry is not always considered complete at the first evidence of fatigue spalling. Although some other industries allow for the remanufacture and restoration of bearing assemblies, the aggressive raceway fatigue regrinding practices allowed by the AAR are not commonly permissible in other industries. These remanufacturing practices adversely influence subsurface stress magnitudes below the raceway surface, as they reduce the effective length of the raceway and can create stress risers. Engineering tools like the novel modeling method presented in this paper can be used by bearing designers to evaluate the impact of surface discontinuities, at the center or edge of the raceway, on the overall stress state of bearing raceways. For the various types of raceway conditions detailed above, a new tool was developed using finite element methods to simulate the stress state of the bearing under complex raceway contact geometries or adverse load conditions. The finite element contact stress tool was successfully validated using proven Hertzian contact theory. Peak maximum shear and von Mises subsurface stress predictions between the finite element model and conventional contact theory agreed within .001 inches, with regards to peak stress depth below the surface, and 10,000 psi, with regards to peak stress magnitude. This newly developed methodology will be used in future studies to analyze other load conditions and raceway contact geometries that cannot be analyzed with basic Hertzian contact theory, in order to illustrate practical application of the tool. Specifically, overload conditions are analyzed in the work presented. Furthermore, a proposed methodology for future work related to the examination of the stress state created by current AAR bearing reconditioning acceptance standards related to raceway impact damage and spall repair will be introduced.

Developing and maintaining a healthy work environment is an important consideration to the rail industry. Several theories have been advanced to examine, understand, and influence how workers function and interact within their working environments. These include motivational theories such as Taylor’s Theory of Scientific Management and Maslow’s Hierarchy of Needs, models of moral develop such as developed by Kohlberg and Gilligan, theories of personality types like Myers–Brigg and Keirsey, and the theory of cultural dimensions developed by Hofstede. Positive work environments can contribute to safe and efficient operations, while negative work environments almost inevitably degrade performance and increase the potential for injury and accidents. Therefore understanding and managing these elements properly can greatly contribute to better organizational outcomes. This paper will then examine the underlying role of human behavior as determined by these theories appear to have played in 5 incidents at Metro–North Railroad in 2013–2014.

The increasing progress in the field of satellite navigation systems (GNSS, SBAS) in the recent decades supports effort to use it for determination of train position for railway safety-related systems. Satellite-based augmentation systems (SBAS) such as WAAS in the USA, and EGNOS in Europe, are available and a new global satellite navigation system Galileo is being built by the European GNSS agency (GSA). The currently available SBAS systems were developed in order to satisfy aviation requirements. But the safety concept on railways is very different from the aviation safety concept. The railway safety concept in Europe is determined by means of the CENELEC standards (EN 50126, EN 50129, EN IEC 61508). So it is necessary to find a way how to use GNSS systems in accordance with strict railway standards. The main problem is attainment of sufficient integrity of position solution [5, 12]. Satisfaction of safety integrity level 4 (SIL4) is necessary for railways [6, 7, 8, 9]. At the beginning, it can provide low-cost controlling system for the local, regional and freight railway lines. GNSS provides a 3D position (position in horizontal and vertical plane). The value of altitude is cruical for application in aviation, in ground transportation this value is not so important. On the contrary, the value of horizontal position is cruical. For the purpose of increasing the integrity of GNSS-based position determination we propose a new method of the detection of a GNSS horizontal position error based on the relation between vertical and horizontal position error. As was mentioned for example in [4], as GPS is a three dimensional positioning system, errors between any two coordinates may be correlated, and so there can be relations between errors in individual dimensions. The general 3D GPS-based position solution can be divided into two parts: - 2D horizontal position - 1D vertical position We investigated the relation between errors in the horizontal and vertical plane in real data measured by a GNSS receiver. It was static measurement and the antenna location was exactly known. The vertical position provided by GNSS is not constant. In ground transportation we can mostly make an assumption of nearly a constant value of altitude during the ride. Especially in railway transportation the changing of altitude during the ride is limited by many factors (railway standards, properties of track) So we investigate the possibility of using values of altitude to estimate a position error in the horizontal plane. As the receiver determines the values of the vertical position in real time, the detection of the horizontal position error based on the values of altitude can help detect the actual position error in horizontal plane during the train ride also in real time. The sensitivity of this method to errors in pseudoranges (error caused by multipath) was also investigated. This was done by simulation with software receiver Pegasus (Eurocontrol). The analysis was based on real data from GNSS.

Since High-Speed Rail (HSR) began planned and constructed, many involving enterprises obtain interests from the process. But with increasing number of High-Speed railways being planned, constructed, and then operated, it will inevitably bring more improvement on the ability of these involving enterprises. So, no matter policy planers and the entrepreneurs or investors, understand the inner mechanism of the mutual influence between the development of High-Speed Rail and the improvement of involving enterprises is a key point to keep harmonious and efficient development of infrastructure construction simultaneously with the enterprises. In this paper, it is presented an example of an experimental study investigating the effects of high speed rail’s construction and operation on these involving enterprises in each link of this high speed rail industry chain. As we know, social division of labor improves the efficiency of society, and with more detailed-oriented division, more enterprises and experts are engaged in one or several domains. Thus the construction and operation of high speed way are complex processes completed by numerous enterprises, each one or some of which only need to deal with one part. By sorting the industry chain of high speed rail, 50 listed enterprises are selected with their operated data from 2006 to 2010. The comprehensive evaluation system of enterprises ability is modeled by factor analysis method to obtain the key factors, which affect the development of enterprises. The results show the ability of these enterprises are influenced by their scale, profitability, debt, operation ability and progressive ability, and the enterprises in different link own their special abilities compared with those of other links. And next, from the time dimension, the abilities of enterprises have been changed from 2006 to 2010, especially one or several abilities that summarized in the previous part. So via variance analysis, the change laws of ability are explored in the process of construction and operation of high speed rail, which, on one hand, is confirmed the promotion of high speed rails to these abilities of enterprises, on the other hand, shows the inner mechanism and rules in the process.

The more demanding safety and comfort requirements combined with the increasing maximum speed of trains have lead to a growing concern in aspects such as the determination of the modal parameters of railway vehicles. Until now, the modal parameters of a vehicle have been obtained by EMA (Experimental Modal Analysis) based on the application of an impact force on the vehicle frame. However this kind of test is not optimal for railway vehicles because, due to their large dimensions, an impact force is unable to excite all the points of the structure. Also, with this method only the structural modes can be analyzed. Because of these drawbacks, a new modal analysis methodology is proposed, in which the excitation force comes from a specially designed shaker mounted under a point of a test track. In this manner, real excitation conditions can be simulated and it allows to determine not only the structural modes, but also the vibration modes associated with the suspensions. In first place, a description of the test facilities is presented. Afterwards, we present a test carried out in one of the coaches of a high speed train. The instrumentation employed, test methodology and test results are described. Finally, the test results are compared with the results obtained from a modal test in which impact excitation was used. Also the vibration modes obtained in the test are compared with the theoretical ones, which have been calculated with a combination of a FEM (Finite Element Method) and a MBS (Multi-Body Simulation).

Railway distributed system integration needs to realize information exchange, resources sharing and coordination process across fields, departments and application systems. And railway data integration is essential to implement this integration. In order to resolve the problem of heterogeneity of data models among data sources of different railway operation systems, this paper presents a novel integration data model of spatial structure, a XML-oriented 3-dimension common data model. The proposed model accommodates both the flexibility of level relationship and syntax expression in data integration. In this model, a spatial data pattern is used to describe and express the characteristic relationship of data items among all types of data. Based on the data model with rooted directed graph and the organization of level as well as the flexibility of the expression, the model can represent the mapping between different data models, including relationship model and object-oriented model. A consistent concept and algebraic description of the data set is given to function as the metadata in data integration, so that the algebraic manipulation of data integration is standardized to support the data integration of distributed system.

In the Northern areas the total thickness of structural layers in railway embankments is primarily governed by the design against harmful effect of seasonal frost. Because practically no frost heave can be allowed to take place on railway tracks with normal speed passenger traffic, the embankment must typically be built up to two or even two and a half meters thick. Meantime, the embankments have typically fairly steep slopes, for instance in Finland track embankments are normally built using a slope ratio of 1:1.5. Introduction of higher allowable axle loads and traffic speeds is, however, exposing the embankments structures to continuously increasing intensity of repeated loading which is also increasing the rate of permanent deformations accumulating into the embankment structure. In practical terms the embankment is widening as it deforms and the respective movements of the track must be compensated by more frequent maintenance actions. The most straightforward measures to increase the internal stability of a railway embankment are to make the embankment wider and/or to reduce the slope steepness of the embankment. Both of these actions mean, however, larger space requirement for the railway track and, above all, extensive increase in the use of high-quality non-frost-susceptible aggregate materials in connection with the embankment construction or renovation. Therefore, taking into account both the construction time costs on one hand and the maintenance costs of the track on the other hand, optimisation of the embankment dimensions and shape is an important issue regarding the life cycle costs of a railway line. In a research project going on at the Laboratory of Earth and Foundation Structures of the Tampere University of Technology the above mentioned problem is being studied by in-situ monitoring of a full scale railway track embankment having sections that are shaped in different embankment widths and slope angles. The long term deformations of the embankment have been monitored for about three years in addition to which also the short term responses of the embankment structure have been measured while trains are passing over the monitoring sections. In addition, model scale (1:4) test structures with different embankment widths and slope angles have been tested in laboratory using a loading system consisting of five hydraulic actuators operating consecutively so as to simulate the loading effect of a moving train. The results obtained so far indicate clearly that it is not only the embankment width and slope angle that are decisive concerning the permanent deformation behaviour of the railway embankment, but also the subgrade stiffness plays an important role in the overall performance of the embankment structure.

Two grade-crossing impact tests were conducted in June 2002 at the Federal Railroad Administration’s (FRA’s) Transportation Technology Center in Pueblo, Colorado as part of the FRA’s research into passenger equipment crashworthiness. In both of these tests a cab car moving at approximately 14 mph impacted a standing coil of steel supported by a frangible table. The coil was positioned such that the left-side corner post of the cab car sustained the brunt of the impact. The cars were instrumented to measure the accelerations of the carbody, the displacements of the suspensions, the displacements of the corner posts, and the strains in selected structural members. The coil was instrumented to measure its three-dimensional acceleration, including yaw, pitch, and roll. On-board and wayside high-speed film and video cameras were used to record the impact. On June 4, 2002 a cab car compliant with general industry practice circa 1999 was tested and on June 7, 2002 a cab car compliant with current FRA regulations and American Public Transportation Association (APTA) Standards and Recommended Practices for Rail Passenger Equipment was tested. The tests themselves were conducted in response to a recommendation from the APTA Passenger Rail Equipment Safety Standards (PRESS) Committee to measure the crashworthiness performance of alternative cab car end structures. During the test of the 1990’s design, the corner post failed, eliminating the survival space for the operator. During the test of the state-of-the-art design cab car, the corner post remained attached and deformed less than 9 inches, preserving space for the operator. Prior to the test, crush analyses were conducted to determine the force/crush characteristics of the two end structure designs, as well as their modes of deformation. Collision dynamics analyses were also conducted to determine the extent of crush and the gross motion of the car and coil. This paper describes the analysis of the crush behaviors of the two different end structure designs. A companion paper describes the results of the collision dynamics analyses. The crush of the cars was analyzed using detailed finite-element models. The impact end of each car was modeled, including approximately 1/4 of the length of the car. The back end of the cab car model was fixed, and its end structure was impacted by an initially moving cylinder with the same mass and dimensions as the steel coil used in the tests. Prior to the tests, runs were made with the models with and without material failure. This approach allowed calculation of an upper bound and a lower bound on the force/crush characteristics. The pre-test predictions of the analysis of the state-of-the art car including material failure very closely match the results of the test for the force/crush characteristic, strains at the measured locations, the geometry of the deformed structure, and the locations and extent of material failure. The pre-test predictions of the analysis of the 1990’s design also closely match the test measurements, however, the extent of material failure predicted was slightly less than observed in the test; failure of the corner post was predicted to occur at a speed of a 1.6 mph (approximately 10%) greater than the test speed. A more sophisticated implementation of the material failure modeling helped bring the model results into very close agreement with the test measurements.

On December 3, 2003, a single-car impact test was conducted to assess the crashworthiness performance of a modified passenger rail car. A coach car retrofitted with a Crash Energy Management (CEM) end structure impacted a fixed barrier at approximately 35 mph. This speed is just beyond the capabilities of current equipment to protect the occupants. The test vehicle was instrumented with accelerometers, string potentiometers, and strain gages to measure the gross motions of the car body in three dimensions, the deformation of specific structural components, and the force/crush characteristic of the impacted end of the vehicle. The CEM crush zone is characterized by three structural components: a pushback coupler, a sliding sill (triggering the primary energy absorbers), and roof absorbers. These structural mechanisms guide the impact load and consequent crush through the end structure in a prescribed sequence. Pre-test activities included quasi-static and dynamic component testing, development of finite element and collision dynamics models and quasi-static strength tests of the end frame. These tests helped verify the predicted structural deformation of each component, estimate a force-crush curve for the crush zone, predict the gross motions of the car body, and determine instrumentation and test conditions for the impact test. During the test, the passenger car sustained approximately three feet of crush. In contrast to the test of the conventional passenger equipment, the crush imparted on the CEM vehicle did not intrude into the passenger compartment. However, as anticipated the car experienced higher accelerations than the conventional passenger car. Overall, the test results for the gross motions of the car are in close agreement. The measurements made from both tests show that the CEM design has improved crashworthiness performance over the conventional design. A two-car test will be performed to study the coupled interaction of CEM vehicles as well as the occupant environment. The train-to-train test results are expected to show that the crush is passed sequentially down the interfaces of the cars, consequently preserving occupant volume.